Metastatic prostate cancer generally responds initially to medical or surgical castration, followed by eventual resistance as castration-resistant prostate cancer (CRPC), which is driven by the metabolic capability of tumors to reconstitute potent androgens, mainly from dehydroepiandrosterone (DHEA)/DHEA-sulfate, and in turn stimulate the androgen receptor (AR). Chang et al., Cell 154, 1074-1084 (2013). Abiraterone (Abi; administered orally as Abi acetate), a steroidal drug, inhibits 17α-hydroxylase/17,20-lyase (CYP17A1), blocks androgen synthesis and prolongs survival, even after treatment with docetaxel chemotherapy. de Bono, et al., The New England journal of medicine 364, 1995-2005 (2011). However, resistance to abiraterone therapy can also develop. Accordingly, there remains a need for methods of treating steroid-dependent diseases such as castration-resistant prostate cancer.